OA = (1,1),OB = (2,3),OC = (m+1,m-1)A、B、C能构成三角形=> A,B,C 不在同一直线上AB = OB-OA= (1,2)AC = OC -OA= (m,m-2)A,B,C 不在同一直线上 =>AB ≠kAC (where k is a constant)(1,2)≠(m,m-2)=> m ≠ (m-2)/2=...